Rationale and design considerations for a semantic mediator in health information systems.

Rapid development of community health information networks raises the issue of semantic interoperability between distributed and heterogeneous systems. Indeed, operational health information systems originate from heterogeneous teams of independent developers and have to cooperate in order to exchange data and services. A good cooperation is based on a good understanding of the messages exchanged between the systems. The main issue of semantic interoperability is to ensure that the exchange is not only possible but also meaningful. The main objective of this paper is to analyze semantic interoperability from a software engineering point of view. It describes the principles for the design of a semantic mediator (SM) in the framework of a distributed object manager (DOM). The mediator is itself a component that should allow the exchange of messages independently of languages and platforms. The functional architecture of such a SM is detailed. These principles have been partly applied in the context of the HELIOS object-oriented software engineering environment. The resulting service components are presented with their current state of achievement.

An object oriented computer-based patient record reference model.

In the context of health care information systems based on client/server architecture, we address the problem of a common Computer-based Patient Record (CPR). We define it as a collection of faithful observations about patients care, with respect to the free expression of physicians. This CPR model supports several views of the medical data, in order to provide applications with a comprehensive and standardized access to distributed patient data. Finally, we validated our CPR approach as a primary data model server for an application for hypertensive patient management.

A development environment to create medical applications.

This paper describes a Development Environment for medical applications developers coupling Reuse and Object-Oriented technologies. It presents the two main phases of the reuse process, the reusable component creation and the reusable component use, and stresses on the very nature of reusable development components. We provide both a classification model for those reusable components that is a support for an efficient and simple retrieval mechanism, and a reusable component model that considers the same way components of large and low-granularity levels (e.g., application frameworks and methods of a given class). The reusable component model is based on the underlying idea that development components are not operational components since they do not have the same purpose. This model first represents each component as an aggregation of other sub-components, together with all information needed for its retrieval (e.g., classification and facets), its understanding (e.g., informal functional description), and its dependencies with other development components, in particular the applications in which it occurs, since applications are considered here as abstract development components.

The HELIOS Medical Connection Services.

This paper presents the design and implementation of the HELIOS software component that deals with integration of medical applications in health information networks. The problem of interoperability between health information systems based on different data exchange syntaxes is first discussed. A meta-model, relying on CEN TC251 recommendations, is then presented as a possible solution to this problem and a message description language including these recommendations is proposed. Using this meta-model, the Medical Connection Services that comprises a generic message processing automaton, a resource manager and a mapper is able either to interpret messages expressed in a given syntax (e.g., EDIFACT, ASTM) and map them to the application objects or to automate the translation of the messages in another syntax. Special focus is given on the position of the Medical Connection Services within the HELIOS integration strategy (i.e., through data, presentation and communication). The problem of semantic heterogeneity is then discussed.

A reuse oriented Development Database: the HELIOS Object Information System.

This paper describes the Development Database of a Software Engineering Environment (SEE), that couples reuse and object-oriented technologies. We propose a classification model for the repository of reusable components that is a support for an efficient retrieval mechanism, and a reusable component model that considers components of large and low-granularity levels (e.g., application frameworks and methods of a given class). The reusable component model is based on the underlying idea that development components are not operational components since they do not have the same purpose. This model first represents each component as an aggregation of other sub-components, together with all information needed for its retrieval (e.g., classification and facets), its under-standing (e.g., informal functional description) and its dependencies with other development components, in particular the applications in which it occurs, since applications are considered also as abstract development components. This approach was tested thanks to an existing application which was loaded into the SEE. From that moment, it was possible to regenerate a new application in a reasonably short time. Moreover, the existence of a retrieval tool permits to validate the development components classification, but also put forward the importance of the qualification step. In particular, the versioning should be carefully processed. Furthermore the fact that all the development objects are built on an homogeneous model allows easier tools management and interapplication reusability.

A software engineering approach for medical workstations development.

Multimedia medical workstations represent the natural tool for accessing the hospital information system environment. They are complex medical systems that have to gather, in a single framework, a large collection of components dealing with multimedia medical objects. To remain current with both medical practice and with advances in the computer science field, they have to allow the iterative addition of new functions to the set of existing ones. In this paper, after a survey of commonly required medical workstation functional components, we shall try to discuss how a software engineering approach can streamline the development of a medical workstation. Different software engineering tools needed to build the functional components of a workstation are described. Their integration in a single dedicated environment is considered through four perspectives: data, presentation, communication and control. Benefits and limitations of an object-oriented approach are discussed.

Using a meta-model to build a connection service in an object oriented medical application development environment.

Interoperability is a key issue in distributed health information systems. This paper presents the design and implementation of the Connection Service (CS) component of the HELIOS medical software engineering environment. An exchange message meta-model based on CEN TC251 recommendations and a message description language are proposed. Using this meta-model, the CS is able either to interpret messages expressed in a given syntax (e.g., EDIFACT, ASTM) and map them to the application objects or to automate the translation of the messages in another syntax. It is concluded that this meta-model approach contributes to the management of semantic heterogeneity.

An approach for the evaluation of software engineering environments in medicine.

This article examines several criteria for the evaluation of software engineering environments (SEE) in medicine. The study is restricted to the evaluation of the SEE itself, not of its by-products which are the medical applications developed with the SEE. Basic principles for an evaluation methodology are presented. They consist in determining the evaluation objectives and judging a SEE according to criteria which are grouped into three broad categories--functional, generic and environmental. Each category reflects a particular domain of evaluation of the SEE. Methods of measurement and questions highlighting these specific areas are mentioned. Criteria are extracted from the list of objectives that follows the HELIOS European AIM project of the Commission of the European Communities. Special emphasis is drawn on the criteria for which the medical specificity and usefulness of a SEE can be approach. For this purpose a method of measurement of such appropriateness is proposed.

Spontaneous peritonitis in cirrhotic hospital in-patients: retrospective analysis of 101 cases.

One hundred and one patients with cirrhosis resulting from alcohol abuse, admitted to Broussais University Hospital, Paris, between January, 1986 and December, 1989 were assessed for infection of the ascitic fluid using clinical and cytobacteriological criteria. All of 46 patients (45.5%) with clinical signs and symptoms of peritonitis had an ascitic fluid polymorphonuclear (PMN) count > 250 cells/mm3. Bacteria could be isolated from the ascitic fluid of 23 patients (50%). Twenty-six bacterial strains were isolated (there was more than one strain in two samples). Escherichia coli was found in 14 cases. It is noteworthy that no anaerobes were grown. Mortality, biochemical parameters and clinical features correlated significantly with an ascitic fluid PMN count > 250 cells/mm3. High mortality correlated with a PMN count > 1000 cells/mm3 (70% vs. 33%).

Bayesian statistics as applied to hypertension diagnosis.

This paper deals with the following hypertension diagnoses: essential hypertension and five types of secondary hypertension: fibrodysplasic renal artery stenosis, atheromatous renal artery stenosis, Conn's syndrome, renal cystic disease, and pheochromocytoma. Only blood pressures, general information and general biochemical data are taken into account. Nineteen items were finally selected, by statistical investigation of experimental data, as being both discriminative and independent. The marginal density distributions of every item, and then joint density distribution functions were determined within six types of hypertension. The frequency of a given hypertension type within the hypertensive patients was used as prior probability of this state. The loss matrix was established by medical arguments. The expected loss corresponding to six possible decisions could thus be calculated for all cases. Both the ratio of secondary hypertensions that could be inferred from our set of data (not including the results of complementary tests) and that of correct "essential" hypertension diagnosis proved to be satisfactory.

Computer-assisted techniques for evaluation and treatment of hypertensive patients.

An integrated approach, progressively implemented in the ARTEMIS system since 1975, is described for the computerized management of hypertensive patients. From a medical point of view, computerized programs can be used to memorize patients' individual records and profiles, to facilitate patient management and follow-up, to store medical knowledge about hypertension and to provide facilities for decision making at the level either of the individual patient or of the population followed up. From a technical point of view, the methodology used integrates data and knowledge management facilities into the same software. Five hypertension clinics are presently using the system in France and more than 22,000 records have been registered. Answer rates to 12 mandatory questions regarding past history and examination at first visit were superior to 95% in 19,601 records created between January 1976 and December 1987. Patient database interrogation can be used to evaluate the sensitivity and specificity of various signs and symptoms for the diagnosis of secondary hypertension, and to predict, for each patient, his/her cardiovascular risk, the risk of drop-out, the risk of insufficient blood pressure control and the probable blood pressure level. It also serves to test the content and validity of the associated expert system which is progressively built up. A prospective evaluation of the performance of the expert system on 80 cases of hypertension showed overall agreement between the specialists and the expert system ranging from 58 to 91% depending on the decision.(ABSTRACT TRUNCATED AT 250 WORDS)